Analytical Methods to Study Kinetics of Fermentation

摘要

The volumetric determination of ethanol in the presence of glucose, buffer salts, and yeast requires a special analytical technique similar to that for determining alcohol in blood devised by Harger. In the special technique as described in this report the yeast cells, which would chemically interfere with the volumetric determination, are flocculated with lead acetate followed by centrifugation (greater than 2800 RPM). The clarified samples (4-6 ml) were found to be yeast-free and ready for subsequent glucose and ethanol determination. The glucose rest concentration of clarified samples was then determined by measurement of the optical rotation with a polarimeter. Knowing this rest concentration of glucose and its stoichiometric equivalent of dichromate, a correction factor was calculated. This correction factor was then used in the oxidimetric determination of ethanol. The oxidimetric titration for determination of ethanol was performed with potassium dichromate. (Author)